Field of the Invention
The invention relates to a range finder and prism assembly thereof.
Description of the Related Art
Taiwan Patent No. TW594052 (which corresponds to U.S. Pat. No. 7,031,062) discloses a prism assembly and a range finder using the prism assembly, wherein the prism assembly includes four surfaces for light to enter/exit. By this arrangement, an infrared beam entering the prism assembly undergoes only one total internal reflection and exits the prism assembly in a direction differing from its original propagation direction. In addition, a visible light beam entering the prism assembly undergoes a reflection and four total internal reflections, and exits the prism assembly without changing its original propagation direction. Alternatively, the visible light beam entering the prism assembly undergoes three total internal reflections and exits the prism assembly in a direction differing from its original propagation direction.